Zebra, Grevy's

Equus grevyi

Grevy's zebra is the largest of all wild equines. It is 8-9 feet in length from head to tail, with a 15-30 inch tail, and stands 4'7"-5'3" high at the shoulder. They weigh 770-990 pounds. The stripes are narrow and close-set, being broader on the neck, and extending to the hooves. The belly and area around the base of the tail lack stripes. The ears are very large, rounded, and conical. The head is large, long, and narrow, particularly mule-like in appearance. The mane is tall and erect; juveniles have a mane extending the length of the back.

Family

Equidae

Order

Perissodactyla

Class

Mammalia

Range

Kenya, Somalia, Eritrea and SE Ethiopia

Habitat

Dry desert regions and open grasslands

Life Expectancy

Up to 18 years in the wild; perhaps up to 30 years in captivity.

Sexual Maturity

About 4 years (1461 days)

Diet

In the wild, they feed mostly on grasses but they will also eat fruit, shrubs, and bark; in the Zoo they are fed a scientifically developed, commercially available pelleted grain and hay.

Status

IUCN – Endangered; CITES – Appendix I

Behaviors

Grevy’s zebras may spend 60-80% of their days eating, depending on the availability of food. Their well-adapted digestive system allows them to subsist on diets of lower nutritional quality than that necessary for herbivores. Also, Grevy’s zebras require less water than other zebras. Grévy’s zebra is similar to the ass in many ways. Behaviorally, for example, it has a social system characterized by small groups of adults associated for short time periods of a few months. Adult males spend their time mostly alone in territories of 1.2 – 7.5 mi 2 (2 - 12 km²), which is considerably smaller than the territories of the wild asses. The territories are marked by dung piles and females who wander within the territory mate solely with the resident male. Small bachelor herds are known. Like all zebras and asses, males fight amongst themselves over territory and females. The species is vocal during fights (an asinine characteristic), braying loudly. However unlike other zebras, territory holding Grévy’s zebra males will tolerate other males who wander in their territory possibly because non-resident males do not try to mate with the resident male’s females nor interfere in his breeding activities. Grévy’s zebras mate year-round. Females experience a 2-9 day estrus period every 19-33 days. During their estrus, they are receptive to mating for 2-3 days. Gestation of the zebra lasts 350-400 days, with a single foal being born. A newborn zebra will follow anything that moves and thus new mothers are highly aggressive towards other mares a few hours after they give birth. This prevents the foal from imprinting on another female as its mother. The newborn zebra first stands during the first 6-14 minutes following birth. It is able to walk within a half an hour of birth, and can run for short distances by the time is 45 minutes old. The young nurse for 275 days.

Adaptions

With all of the stripes closer together and thinner than most of the other zebras, it is easier to make a good escape and to hide from predators. The social structure of Grévy’s zebra is well-adapted for the dry and arid scrubland and plains that it primarily inhabits, in contrast to the more lush habitats used by the other zebras. To adapt to an arid lifestyle, Grévy’s zebra foals take longer intervals between suckling bouts and do not drink water until they are 3 months old. They also reach independence from the mare sooner than other equids.

Special Interests

The species is named after Jules Grévy, who, in the 1880s, was given one by the government of Abyssinia. François Paul Jules Grévy (15 August 1807 - 9 September 1891) was a President of the French Third Republic and one of the leaders of the Opportunist Republicans faction. Given that his predecessors where monarchists who tried without success to restore the French monarchy, Grévy is seen as the first real republican President of France. Grevy’s zebra was the first zebra to be discovered by the Europeans and was used by the ancient Romans in circuses. Later, it was largely forgotten about in the Western world until the seventeenth century. Grevy’s zebra occupies the niche between the water-dependent plains zebra and the arid-adapted wild ass, living in arid and semi-arid habitat comprised of grass and shrubland with permanent water available. Predominantly grazers, Grevy’s zebras live on forbs and grasses but during extremely dry periods they also browse. Grevy’s zebra can go without water for up to five days however if lactating, the females must drink at least every other day in order to maintain milk production.

Folklore

African Legends - How the Zebra Got his Stripes - There once was an arrogant Baboon, a self-appointed “Lord of the Water”. He guarded one of the only sources of water that remained during times of drought, a small pool, and forbid any of the other animals from drinking there. Legend has it that one day a Zebra and his son arrived at the pool. The weather had been very dry and hot, and there was little water to be found anywhere. They went to have a drink when suddenly a voice boomed “Go Away! I am the Lord of the Water, and this is my pool”! The Zebras looked up, startled, and saw the angry Baboon sitting by his fire. “Water belongs to everyone, not just to you monkey face”, shouted the young Zebra. “Then you must fight me for it if you want to drink” challenged the baboon, and attacked the young Zebra. The two fought savagely for what seemed an eternity until with a furious kick, the Zebra sent the Baboon flying through the air until he landed amongst the rocks. Till this day, the Baboon has a patch on his bottom where he landed. The tired Zebra staggered, and fell through the Baboons fire, scorching his white coat and leaving him with black stripes across it. The terrified Zebras dashed away back to the plains where they forever remained. The arrogant Baboon and his family still live among the rocks and spend their days challenging intruders, holding their tails aloft to ease the pain of the bare patch of skin where they landed.

Conservation

A few decades ago, more than 15,000 Grevy’s zebra inhabited Africa. Today, fewer than 2,500 remain. The greatest threats facing the species today are habitat fragmentation and loss as more land is converted to agricultural use. Overgrazing by livestock is leading to significant environmental degradation. Grevy’s zebra compete for food with the ever-increasing livestock population and with agricultural crops for water. With land degradation worsening each year, the distances between available grazing and the water required by Grevy’s zebra mothers means that they have to travel longer and longer distances, resulting in increasingly high foal mortality, which is one of the major threats to the survival of the species. In the past, Grevy’s could be found in Ethiopia, Somalia, and Northern Kenya. Now they are considered extinct in Somalia, with a small number in Ethiopia (less than 150) and the remainder in Northern Kenya. Today, Grevy’s zebras survive in only a few protected areas. Of the world population (less than 2,300) over 20 % are found on Lewa. Lewa was once a cattle ranch worked by the Craig/Douglas family for 50 years; it then became a heavily guarded black rhino sanctuary, and it is now the headquarters for a non-profit wildlife conservancy, which has gained a world-wide reputation for extending the benefits of conservation beyond its borders. The Lewa Wildlife Conservancy works as a catalyst for the conservation of wildlife and its habitat. It does this through the protection and management of species, the initiation and support of community conservation and development programmes, and the education of neighbouring areas in the value of wildlife. Today, over 70 species of mammals and 350 species of birds are found on Lewa. The number of Grevy’s zebras has increased substantially here on Lewa. In 1991 the Lewa Grevy’s population numbered 259 individuals and today fluctuates between 400-500 animals. The reasons for the population increase on Lewa are: 1) Lewa is a protected area, so hunting for subsistence or commercial use has been completely eliminated; and, 2) livestock numbers have been greatly reduced, thereby reducing competition for grazing and water grounds for Grevy’s zebras. In the future, the balanced populations on Lewa and in other protected areas will be vital to ensuring the survival of the Grevy’s zebra and will be used as a reservoir for restocking the national parks. From the IUCN: Listed as Endangered as Grevy’s Zebra is estimated to have declined by more than 50% over the past 18 years based on direct observation and potential/actual levels of exploitation. In addition, the current total population is estimated at 750 mature individuals, with the largest subpopulation estimated at 255 mature individuals. Grevy’s have undergone one of the most substantial reductions of range of any African mammal. Historically, they ranged east of the Rift Valley in Kenya to western Somalia, and in northern Ethiopia from the Alledeghi Plain through the Awash Valley, the Ogaden, and north-east of Lake Turkana in Ethiopia to north of Mt. Kenya and south-east down the Tana River in Kenya (Bauer et al. 1994). Currently, Grevy’s’ Zebra have a discontinuous range, and are found from the eastern side of the Rift Valley in Kenya to the Tana River. There is a small, isolated population in the Alledeghi Plains northeast of Awash N.P. in Ethiopia. From Lake Ch’ew Bahir in southern Ethiopia, the population extends to just north of Mt. Kenya although a few animals are found further southeast along the Tana River. A small introduced population survives in and around Tsavo East N.P. in Kenya. They are considered to be extirpated from Somalia (where the last confirmed sightings date to 1973) and from Djibouti; there are no confirmed records that the species ever occurred in Eritrea (Yalden et al. 1986, Bauer et al. 1994). Sightings from southern Sudan require verification (Williams 2002, in press). The major threats to Grevy’s Zebra include: reduction of available water sources; habitat degradation and loss due to overgrazing; competition for resources; hunting; and disease (Rowen and Ginsberg 1992; Williams 2002, in press). In Kenya, hunting for skins in the late 1970s may have contributed to the observed decline, although recent data suggest that the continuing decline in this country is attributable to low recruitment due to low juvenile survival. This is a result of competition for resources – both food and access to water – with pastoral people and domestic livestock (Williams 1998). However, a low level of hunting of Grevy’s Zebra for food and, in some areas, medicinal uses continues (Williams 2002, in press). Furthermore, the water supply in critical perennial rivers has declined, most notably in the Ewaso Ng’iro River where over-abstraction of water for irrigation schemes has reduced dry season river flow by 90% over the past three decades (Williams 2002, in press). In Ethiopia, killing of Grevy’s Zebra is the primary cause of the decline (F. Kebede pers. comm. 2007). Recently, Muoria et al. (in press) recorded an outbreak of anthrax in the Wamba area of southern Samburu, Kenya, during which more than 50 animals succumbed to the disease. It is protected by law in Ethiopia and by a hunting ban in Kenya.

Jacksonville Zoo History

Jacksonville Zoo exhibited this zebra from 1966 to 1972, and the Grevy’s Zebra returned to our collection in 2007.